This invention relates generally to a power line communication system and more particularly, to a power line communication system that uses signal attenuation caused by boundary components to create regions in the power line communication system.
Typically, geometric harmonic modulation (GHM) allocates signaling energy into lobes, tones or different frequencies that are evenly spaced. The GHM signaling waveforms are true spread spectrum signals in that the signal bandwidth (i.e., the bandwidth from the lowest frequency tone to the highest frequency tone) exceeds the information bandwidth conveyed by the GHM transmission. GHM communication is well suited for power line communication applications since the GHM signals can be transmitted through power line components such as distributors and transformers. However, GHM signals can become severely attenuated by capacitor banks located on the power line. In addition, attenuation can be caused when a GHM signal passes through underground cable or when the GHM signal passes an underground cable branch because the underground cables attenuate the GHM signals similar to capacitor banks. The capacitor banks and the underground cables can also be referred to as boundary components. The signal attenuation caused by the capacitor banks and underground cables is undesirable because the attenuation adversely affects the efficiency of the GHM transmission and the integrity of the information being transmitted.
Typically, communication networks for automated meter reading and load control include a master station located at an electrical substation. The master station communicates with meters located at varying distances along the power line from the electrical substation. In these conventional communication networks, the electric utility components (i.e., distribution transformers and capacitor banks, both overhead and underground) are in place and unchanged. It should be appreciated in these conventional communication networks that traps can be located at the capacitor banks. With these conventional communications networks, information is typically transmitted from the master stations to all meters communicatively coupled to the master station. Therefore, even if certain operation are only to be performed by specific meters within a specific region, all the meters coupled to the master station receive the information and process at least a portion of the information to determine whether the specific meter is being addressed.
As such, it is desired to provide a communication network that utilizes the attenuation effects associated with underground cables and capacitor banks. Further, it is also desired to provide a network that enables regionalized and local control of a set of meters to enhance the communication network efficiency using the attenuation effects caused by the boundary components.